Today a boom in local risk assessment begins. That is not because a juicy initial public offering is on offer. So relax, you did not miss something while on holiday.

No, this political risk assessment concerns the ``initial public offering'' of candidates for the September Legislative Council election. The boom in risk assessment erupts today because Legco hopefuls have to start officially declaring their intentions as of this morning. They have until August 4 to file.

The five geographic constituencies will return 30 members, up from 24 in 2000, while the functional constituencies maintain 30 seats. The additional six seats of the geographic constituencies explain some of the increase. And when incumbents such as Szeto Wah retire, candidates who discounted chances of election against such giants reconsider the odds.

Several long-time incumbents of the functional constituencies are also retiring. Retirement is even more important for functional constituencies since most elect by first past the post rules. With both developments - extra geographic constituencies and the retirement of heavy weights - the field has opened up more than ever. There has been much jockeying, especially in the geographic constituencies, with rumours flying of who has decided to stand and with whom on their list, as well as who has decided to leave politics, therefore shifting entrenched voting patterns.

Some rumours and news stories were tactical moves by candidates to spook potential adversaries into declaring their intentions so they could reassess where to declare and with whom to affiliate.

We heard, for example, Chan Yuen-han of the DAB was quitting the party she co-founded and heading a separate list, then not quitting but still heading a separate list. Another article said these stories were mere sensationalism.

We find out the truth today, maybe. Or she might delay filing to confuse her opponents even more.

Keep 'em guessing is a good tactic not just in military campaigns but political campaigns too. Tomorrow the news will be full of stories about who did or did not declare candidacy. We will find out who will really head lists and who will appear lower down the lists as well as how many lists the broad groupings called pan-democrats and pro-government will put forward.

The proportional voting system gives the geographic constituencies a complex set of risk factors. Instead of simple rules - whoever gets the most votes wins - the list-system of geographic constituencies ``allocates'' seats based on the proportion of the overall vote total a list takes.

For example, in the six-seat Hong Kong Island geographic constituency, a list winning 16.67 per cent of the vote will theoretically take one seat. But if a list gets, say, 26.67 per cent of the vote, 10 percentage points more, it could end up with two seats of the six available if other lists get less than 10 per cent in total or as a remainder.

Pan-democrats could take 80 per cent of votes but end up with two-thirds of the seats, depending on how many lists they run and how voters distribute their support.

Parties have been adjusting their order of names as well as number of lists in each geographic constituency. Those down the list get a better chance of election if they have an attractive list-topping associate while those who have weaker names first have chances of making it. However, an attractive name lower down the list just might attract more votes because supporters want to ensure their candidate gets into Legco. It is a gamble.

This will be the riskiest Legco election yet, not just for candidates and parties but also for Beijing. Risking Legco control due to losses in the functional constituencies was not something Beijing imagined with its April intervention which stipulated these constituencies must keep half of Legco to at least 2012. Hitherto, denouncing functional constituencies as anti-democratic in nature, pan-democrats shunned contesting all but the biggest seats. But pan-democrats changed their stance after Beijing's intervention, reasoning they must gain these seats in order to win votes on abolishing functional constituencies.

Odds that nine of 30 functional constituencies will not be contested as in 2000 are nil. The pan-democratic shift raises risks for seats once considered safely pro-government. Raising the risks for politicians - forcing them to compete more fiercely for support - should reward us with better government.